MAE 244 Experimental guide-Pressure Vessels And Strain Transformation Lab 7B .

Experiment guide--Pressure Vessels and Strain Transformation

IntroductionA closed-end cylinder of uniform wall thickness that is subjected to uniformly-distributed

internal pressure, responds to such loading with a uniform, biaxial state of plane stress, along the longitudinal (axial) and the hoop (circumferential) directions. The components of strain (and stress) in any other direction can be determined directly from the longitudinal and the hoop components, either analytically, by using the strain transformation equations or graphically, by applying the principles of Mohr's circle. Either method can be used to determine the principal (maximum or minimum) stresses and their orientation, as well as the maximum values and directions of shearing stress.

ObjectivesExperimental stress /strain analysis of a thin-walled cylinder under a state of uniform

internal pressure, by employing any of two different approaches:

Two-Dimensional strain transformation equations for analytical strain analysis, by using a uniaxial tension specimen.

Mohr's circle for graphical analysis of the biaxial state of stress at certain points on the wall of the pressure vessel.

EquipmentPressure vessel, Portable Strain Indicator and Switch and Balance unit.

Procedure1) Determine the dimensions of the pressure vessel and the orientation of the gages.2) Connect all gages to a strain indicator via a Switch and Balance unit. Zero all readings.3) Connect the cylinder to the pressure hose.4) Increase the pressure in increments of 20 psi to a maximum of 80 psi. Record all strain

readings at each interval.

Report1) Plot the longitudinal strain versus pressure, and the hoop strain versus pressure, respectively.

Is linearity expected? Are the data linear?2) Utilize a table to compare the experimental strains at maximum pressure with the

corresponding theoretical values calculated by thin-walled pressure vessel theory. Discuss the accuracy of the theory.

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MAE 244 Experimental guide-Pressure Vessels And Strain Transformation Lab 7B .

Aluminum Pressure Vessel

Material:6061-T6 Aluminum

Material Properties:E =10.0 × 106

psiG = 3.8 × 106

psiν = 0.33

Strain Gage Information:Strain gage: EA-13-240LZ-120R = 120±0.3%ΩSg = 2.110 ± 0.5%Kt = 0.2±0.2%

Vessel Dimensions:

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